>> Most AAA games already have 200+ ms delays between pressing a button and anything happening on-screen. So there's plenty of room to redesign things to work around that latency in a lot of games

Source please?

I have produced / designed / managed a few AAA games in my life and none of them had a 200ms latency between when you pressed a button and something happened on screen. That delay would be horrible for a fighting game or a driving game. How are you even defining "something happening on screen"?

Let's suppose you are right, that there is a longish latency between when your input is polled and when the game systems fully react. That happens to some extent in RTSs, because changes in the game state are synchronized. But in that case the delay isn't going to hide the network latency, it is going to be added on top of the network latency.